title: Incidental findings from lung CT scans: implications for research.
abstract: BACKGROUND
  We aimed to evaluate the number and nature of incidental findings in CT chest scans in the context of a study of the pulmonary effects of cannabis.
  
  
  METHODS
  Three hundred fifty-seven participants were recruited: 78 cannabis-only smokers, 92 tobacco-only smokers, 106 smokers of cannabis and tobacco and 81 never smokers. All participants underwent a high-resolution CT scan of their thorax. Two radiologists read the scans. Associations between abnormalities and age, sex, tobacco and cannabis smoking status were expressed as odds ratios (OR) with 95% confidence interval.
  
  
  RESULTS
  Seventy-six findings requiring referral or further investigations were found in 71/357 (19.9%) of participants. In multivariate analyses, only older age, OR (per decade) 2.1 (1.4 to 3.0), was associated with a respiratory abnormality on the CT scan. A total of 37/76 (48.7%) of the abnormalities detected were extra-pulmonary, with findings observed across a wide range of organ systems. Only older age, OR (per decade) 1.7 (1.2 to 2.5), was associated with a non-respiratory abnormality.
  
  
  CONCLUSIONS
  The common occurrence of abnormal findings requiring referral or further investigations raises practical, ethical and medico-legal issues which need to be carefully considered in research programmes utilising chest CT scanning.
authors.affiliation: Medical Research Institute of New Zealand, Wellington, New Zealand.
authors.forename: Sarah
authors.initials: S
authors.lastname: Aldington
authors.forename: Philippa
authors.initials: P
authors.lastname: Shirtcliffe
authors.forename: Mike
authors.initials: M
authors.lastname: Nowitz
authors.forename: Andrew
authors.initials: A
authors.lastname: Kingzett-Taylor
authors.forename: Mike
authors.initials: M
authors.lastname: Tweed
authors.forename: Mark
authors.initials: M
authors.lastname: Weatherall
authors.forename: Joan B
authors.initials: JB
authors.lastname: Soriano
authors.forename: Richard
authors.initials: R
authors.lastname: Beasley
mesh_terms: D015897:Comorbidity; D005260:Female; D006801:Humans; D015994:Incidence; D033162:Incidental Findings; D008168:Lung / Q000000981:diagnostic imaging*; D008171:Lung Diseases / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D015995:Prevalence; D013902:Radiography, Thoracic / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D012120:Respiration Disorders / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*